Method and apparatus for forming patterned photosensitive material layer

ABSTRACT

A method for forming a patterned photosensitive material layer over a substrate is described. A photosensitive material layer is formed on a substrate and then exposed. The selected parameters of the photosensitive material layer or between the photosensitive material layer and the predetermined layer are measured for determining whether the exposed patterns of the photosensitive material layer are acceptable. A development step is performed when the exposed patterns of the photosensitive material layer are found to be acceptable. An apparatus for forming a patterned photosensitive material layer is also described, which utilizes the aforementioned method and has a mechanism capable of feeding back offsets of the measured parameters in real time for reducing the cycle time and the rework time in the lithography process.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of a prior application Ser. No. 10/782,369, filed Feb. 18, 2004, now pending, and U.S. application Ser. No. 11/180,092, filed on Jul. 11, 2005, now pending. All disclosures of the two applications are incorporated herewith by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and an apparatus for forming a patterned photosensitive material layer. More particularly, the present invention relates to a method and an apparatus for forming a patterned photosensitive material layer wherein parameters of the latent pattern are measured and offsets of the parameters are fed back in real time.

2. Description of the Related Art

In accompany with the advances in semiconductor industry, numerous high-performance semiconductor apparatuses or integrated circuits including millions of devices like transistors, capacitors and resistors have been developed. To enhance the performance of a semiconductor apparatus or an integrated circuit, its integration degree has to be increased. More specifically, the number of conductive layers has to be increased and/or the critical dimension (CD) of devices has to be reduced.

Since the integration degrees of integrated circuits increase continuously, the alignment precision between different wafer layers or the fidelity of exposed patterns becomes an important issue. For example, when misalignment occurs between conductive lines and plugs of an integrated circuit, the integrated circuit may have a low performance or even fail. Misalignment also occurs easily in doping or ion-implantation process lowering the performance of the integrated circuit.

Generally, the pattern of a film or doping/ion-implantation regions in a film in an integrated circuit is defined by a patterned photoresist layer formed in a lithography process including an exposure step and a development step. Usually, the overlay offset of the patterned photoresist layer is measured after the lithography process for detecting possible misalignment.

FIG. 1 illustrates a process flow for forming a patterned photoresist layer in the prior art. Referring to FIG. 1, a photoresist layer is coated on a wafer (S100), exposed using an exposure tool (S110) and then developed (S120) to form a patterned photoresist layer. The overlay offset between the photoresist patterns and another film is then measured (S130). The next step (S140) is to determine whether the overlay offset is within a tolerable range or not, i.e., whether the photoresist patterns are sufficiently aligned with other films or not. If the answer is yes, the next process is performed (S150). Otherwise, the photoresist layer is removed for rework, and a control signal is fed back to the exposure tool from the overlay measurement tool (S160) so that the exposure conditions in the rework can be adjusted accordingly.

In the prior art, the overlay measurement tool is usually an ACML (product name) tool. However, since the ACLM tool is used after the development step, the development liquid is wasted when a rework is required. Moreover, an ACLM tool cannot measure an overlay offset and feedback a control signal to the exposure tool in real time, so that the wafers processed before reception of the control signal have to be reworked when the overlay offset measured is not within the tolerable range. In addition, an ACML tool is usually quite expensive, thus increasing the manufacturing cost. Furthermore, the use of an ACLM tool requires overlay marks being formed on the scribe line regions of a wafer, so that the scribe line regions cannot be further narrowed.

SUMMARY OF THE INVENTION

Accordingly, this invention provides a method for forming a patterned photosensitive material layer, in which offsets of parameters of the latent patterns are fed back in real time for reducing the cycle time and the rework time in the lithography process.

This invention also provides an apparatus for forming a patterned photosensitive material layer that has a mechanism capable of measuring parameters of the latent patterns and feeding back offsets of the measured parameters in real time. Therefore, the exposed photosensitive material layer is examined in-situ before development, reducing the cycle time and the rework time in the lithography process.

A method for forming a patterned photosensitive material layer of this invention includes the following steps (a)-(d). A photosensitive material layer is formed over a substrate in step (a). Then, the photosensitive material layer is exposed and a parameter of the photosensitive material layer or between the photosensitive material layer and the predetermined layer is measured in step (b). The measured parameter is used to determine whether the exposed pattern of the photosensitive material layer is acceptable or not in step (c). If acceptable, the photosensitive material layer is developed in step (d).

If the latent pattern or image is not acceptable, a step (e) of removing the photosensitive material layer and the above steps (a)-(c) are repeated in sequence for at least one cycle until the exposed pattern is determined to be acceptable in step (c). In each cycle of steps, the exposure condition is calibrated according to the parameter measured in step (b) of the preceding cycle.

According to an embodiment of this invention, a latent image is formed in the photosensitive material layer in the exposure step, and the measurement is done by scanning the latent image with a laser beam and analyzing the signals generated from the laser scanning. The measured parameter is used to determine whether the latent image is acceptable or not.

Another method for forming a patterned photosensitive material layer of this invention includes the following steps (a)-(d). A photosensitive material layer is formed on a substrate in step (a). In step (b), an exposure/measurement tool is used to expose the photosensitive material layer to form a latent image therein and a selected parameter of the photosensitive material layer is measured using the exposure/measurement tool. The measured parameter is compared with a predetermined value in step (c). If the measured parameter is smaller than the predetermined value, the photosensitive material layer is developed in step (d).

If the measured parameter is larger than the predetermined value, however, a step (e) of removing the photosensitive material layer and the above steps (a)-(c) are repeated in sequence for at least one cycle until the measured parameter is found to be smaller than the predetermined value in step (c). In each cycle of steps, the exposure condition is calibrated according to the parameter measured in step (b) of the preceding cycle. The method for calibrating the exposure condition includes, for example, feeding back a control signal generated based on the measured parameter or the offset of the selected parameter to the exposure/measurement tool before the photosensitive material layer is removed to order the exposure/measurement tool to calibrate the exposure condition.

This invention also describes an apparatus for forming a patterned photosensitive material layer according to the abovementioned methods. The apparatus includes at least a photosensitive material coating tool, an exposure/measurement tool, a development tool and a substrate carrying tool. The photosensitive material coating tool is for coating a photosensitive material layer on a substrate. The exposure/measurement tool is used to expose the photosensitive material layer to form a latent image therein and to measure the parameter of the latent image or of the photosensitive material layer or between the photosensitive material layer and the predetermined layer. The development tool is for developing the photosensitive material layer, and the substrate carrying tool is connected between the photosensitive material coating tool, the exposure/measurement tool and the development tool for carrying the substrate between them.

According to an embodiment of this invention, the above apparatus may further include a photosensitive material removal tool. The photosensitive material removal tool may be connected with the exposure/measurement tool and/or the photosensitive material coating tool via the substrate carrying tool.

The substrate carrying tool can carry the substrate to the photosensitive material removal tool or the development tool according to whether the exposed pattern is acceptable or not.

The above exposure/measurement tool is constituted of an exposure module and a measurement module, for example. The exposure module is for forming a latent image in the photosensitive material layer. The measurement module is for measuring the selected parameter of the latent image or of the photosensitive material layer and for feeding back a control signal generated based on the measured parameter to the exposure module.

The exposure module includes an exposure light source and a photomask, for example, wherein the exposure light source may be disposed over the substrate, and the photomask may be disposed between the exposure light source and the substrate. The measurement module may include a laser light source, a signal reception device and a signal feedback device. The laser light source is for scanning the latent image or the photosensitive material layer, the signal reception device is for receiving a test signal generated from the laser scanning that contains the information of the parameter or the offset of the parameter. The signal feedback device is used to generate a control signal based on the test signal and feedback the control signal to the exposure module.

Since the measurement or examination is performed after the exposure step and before the development step in this invention, the offset(s) of the selected parameters can be fed back in real time to avoid undesired rework.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 illustrates a process flow for forming a patterned photoresist layer in the prior art.

FIG. 2 illustrates a process flow for forming a patterned photosensitive material layer according to a preferred embodiment of this invention.

FIG. 2A illustrates a process flow for forming a patterned photosensitive material layer according to another preferred embodiment of this invention.

FIG. 2B illustrates a process flow for forming a patterned photosensitive material layer according to another preferred embodiment of this invention.

FIG. 3 illustrates an apparatus for forming a patterned photosensitive material layer according to the preferred embodiment of this invention.

FIG. 4 schematically depicts the exposure/overlay-measurement tool of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

To solve the aforementioned problems in the prior art, this invention integrates an measurement module and an exposure module together so that the measurement for the parameters of the latent patterns or images can be performed after the exposure step and before the development step and the offsets of the parameters can be decided and fed back in real time. That is, the parameters of the latent patterns or images after exposure are examined in-situ to determine offsets that are fed back for adjusting optimal conditions for the lithography process. By doing so, both the cycle time and the rework time in the lithography process can be reduced effectively.

FIG. 2 illustrates a process flow for forming a patterned photosensitive material layer according to the preferred embodiment of this invention. At first, a substrate is provided with some films or several layers formed thereon. The substrate is, for example, a wafer for fabricating semiconductor apparatuses or integrated circuits, a glass substrate, a quartz substrate, a plastic substrate or a silicon substrate for fabricating display panels, or a plastic substrate or a ceramic substrate for fabricating printed circuit boards (PCB).

Thereafter, a photosensitive material layer is formed on the substrate (S200). The photosensitive material layer can be a positive photoresist layer, a negative photoresist layer, a composite layer of photoresist materials or a material layer sensitive to a light source of a certain wavelength.

The photosensitive material layer is then exposed, a selected parameter of the photosensitive material layer is measured (S210). In this embodiment, the exposure step and the measurement step are performed in-situ; i.e. by the same exposure/measurement tool. The exposure/measurement tool is used to expose the photosensitive material layer to form a latent image therein and then measure the selected parameter of the latent image in the photosensitive material layer. The parameters to be measured are selected according to the requirements of the specification, process windows or product functions. For example, the parameters to be measured or monitored can include the line-width of the latent pattern, the thickness differences (roughness) of the photosensitive material layer over the substrate, or the thickness differences between the exposed portions and the non-exposed portions of the photosensitive material layer, for adjusting the depth of focus (the best focus) or the exposure dosage. Alternatively, the parameters to be monitored or measured can include the overlay offset between the patterned photosensitive material layer and an underlying wafer layer.

In principle, the selected parameter is then used to determine whether the latent pattern is acceptable or not (S220). More specifically, the measured parameter may be compared with a predetermined value to determine whether the exposed pattern of the photosensitive material layer is acceptable or not. If the measured parameter is smaller than the predetermined value, i.e., the selected parameter is within a tolerable range, the photosensitive material layer is developed to form patterns (S230). Thereafter, the patterned photosensitive material layer is used as a mask to perform a film etching process, a doping process, an ion implantation process or a film deposition process to form a patterned film or doped regions (S240). It is noted that the patterned photosensitive material layer formed in this embodiment may be one used to define patterns in a semiconductor device or an integrated circuit, such as, patterns of conductive lines, patterns of openings in a dielectric layer, patterns of conductive plugs or patterns of doped regions. Moreover, the patterned photosensitive material layer may serve as a mask in a film etching process, a doping process, an ion implantation process or a film deposition process. Nevertheless, this invention is not restricted to apply to the above cases, and one skilled in the art may properly modify the aforementioned method for other cases requiring precise alignment without departing from the scope or spirit of the invention.

If the measured parameter is larger than the predetermined value, however, a control signal generated based on the selected parameter is fed back to the exposure/measurement tool, and the photosensitive material layer is removed for rework (S250). The control signal may be in different formats and can include at least an offset or of the selected parameter and/or a series of offsets for other parameters related to the selected parameter. The feedback of the control signal is prior to the removal of the photosensitive material layer, for example. Thereafter, the steps S200-S220 are repeated again, and the exposure condition of the photosensitive material layer is calibrated according to the control signal. If the measured parameter is found to be smaller than the predetermined value in step S220, the photosensitive material layer is developed to form photosensitive material patterns (S230). If the measured parameter is still larger than the predetermined value, the steps S250, S200, S210 and S220 are repeated in sequence for at least one cycle until the measured parameter is found to be smaller than the predetermined value, and then the photosensitive material layer is developed to form desired patterns (S230).

FIG. 2A illustrates a process flow for forming a patterned photosensitive material layer according to the preferred embodiment of this invention. At first, a substrate is provided with several layers formed thereon. The substrate is similar to the substrate described above, and will not be described herein in details.

Thereafter, a photosensitive material layer is formed on the substrate (S200). Taking the overlay offset of an example of the parameter to be measured, the details of the process flow are described in more details hereafter. The photosensitive material layer is then exposed, and the overlay offset between the exposed portions of the photosensitive material layer and a predetermined wafer layer is measured (S210A). In this embodiment, the exposure step and the overlay measurement step are done in the same exposure/measurement tool, which is used to expose the photosensitive material layer to form a latent image therein and then measure the overlay offset between the latent image and the predetermined wafer layer.

The overlay offset value is then used to determine whether the alignment precision of the patterns is acceptable or not (S220A). More specifically, the measured overlay offset may be compared with a predetermined value to determine whether the alignment precision of the photosensitive material layer is acceptable or not. If the overlay offset is smaller than the predetermined value, i.e., the overlay offset is within a tolerable range, the photosensitive material layer is developed to form patterns (S230). Thereafter, the patterned photosensitive material layer is used as a mask to perform a film etching process, a doping process, an ion implantation process or a film deposition process to form a patterned film or doped regions with good alignment precision (S240).

If the overlay offset is larger than the predetermined value, however, a control signal generated based on the overlay offset is fed back to the exposure/overlay-measurement tool, and the photosensitive material layer is removed for rework (S250). The feedback of the control signal is prior to removal of the photosensitive material layer, for example. Thereafter, the steps S200-S220A are repeated and the exposure condition of the photosensitive material layer is calibrated according to the control signal until the overlay offset is found to be in the acceptable range, and then the photosensitive material layer is developed to form patterns (S230).

FIG. 2B illustrates a process flow for forming a patterned photosensitive material layer according to another preferred embodiment of this invention. At first, a substrate is provided with several layers formed thereon. The substrate is similar to the substrate described above, and will not be described herein in details.

Thereafter, a photosensitive material layer is formed on the substrate (S200). Taking the line-width as an example of the parameter to be measured, the details of the process flow are described in more details hereafter. The photosensitive material layer is then exposed, and the line-width of the exposed pattern of the photosensitive material layer is measured (S210B). In this embodiment, the exposure step and the line-width measurement step are done in the same exposure/measurement tool, which is used to expose the photosensitive material layer to form a latent image therein and then measure the line-width of the latent image in the photosensitive material layer.

The value of the measured line-width is then used to determine whether the exposed pattern is acceptable or not (S220B). More specifically, the measured line-width may be compared with a predetermined value to determine whether the fidelity of the exposed pattern in the photosensitive material layer is acceptable or not. If the measured line-width is smaller than the predetermined value, i.e., the measured line-width is within a tolerable range, the photosensitive material layer is developed to form patterns (S230). Thereafter, the patterned photosensitive material layer is used as a mask to perform a film etching process, a doping process, an ion implantation process or a film deposition process to form a patterned film or doped regions (S240).

If the measured line-width is larger than the predetermined value, however, a control signal generated based on the measured line-width is fed back to the exposure/measurement tool, and the photosensitive material layer is removed for rework (S250). The feedback of the control signal is prior to removal of the photosensitive material layer, for example. Thereafter, the steps S200-S220B are repeated and the exposure condition of the photosensitive material layer is calibrated according to the control signal until the measured line-width is found to be in the acceptable range, and then the photosensitive material layer is developed to form patterns (S230).

FIG. 3 illustrates an apparatus for forming a patterned photosensitive material layer according to the preferred embodiment of this invention. The apparatus 300 may be constituted of a photosensitive material coating tool 400, an exposure/measurement tool 500, a development tool 600 and a substrate carrying tool 700. The photosensitive material coating tool 400 is for coating a photosensitive material layer on the substrate. The exposure/measurement tool 500 is used to expose the photosensitive material layer to form a latent image therein and to measure the selected parameter(s) of the latent image in the photosensitive material layer. The development tool 600 is for developing the photosensitive material layer, and the substrate carrying tool 700 is connected between the photosensitive material coating tool 400, the exposure/measurement tool 500 and the development tool 600 for carrying the substrate between them.

The apparatus 300 for forming a patterned photosensitive material layer may further include a photosensitive material removal tool 800. The photosensitive material removal tool 800 may be connected with the exposure/measurement tool 500 and/or the photosensitive material coating tool 400 via the substrate carrying tool 700.

The substrate carrying tool 700 can carry the substrate to the photosensitive material removal tool 800 or the development tool 600 according to whether the measured parameter is acceptable or not. Specifically, when the measured parameter is not acceptable, the substrate carrying tool 700 will carry the substrate to the photosensitive material removal tool 800 for rework. When the measured parameter is within a tolerable range, the substrate carrying tool 700 will carry the substrate to the development tool 600 for developing the photosensitive material layer.

FIG. 4 schematically depicts the exposure/measurement tool of FIG. 3. The exposure/measurement tool 500 is constituted of a measurement module 510 and an exposure module 520, for example. The exposure module 520 is used for forming a latent image in the photosensitive material layer. The measurement module 510 is for measuring the selected parameter of the latent image in the photosensitive material layer or between the photosensitive material layer and the predetermined layer. The measurement module 510 can feed back a control signal generated based on the measured parameter to the exposure module 520 for calibrating the exposure condition.

Referring to FIG. 4 again, the measurement module 510 may include a laser light source 512, a signal reception device 514 and a signal feedback device 516. The laser light source 512 is used to scan the latent image, the signal reception device 514 is for receiving a test signal S_(MEASUREMENT) generated from the laser scanning that contains the information of the measured parameter. The signal feedback device 516 is used to generate a control signal S_(CONTROL) based on the test signal S_(MEASUREMENT) and feedback the control signal S_(CONTROL) to the exposure module 520 for calibrating the exposure condition. The exposure module 520 includes an exposure light source 522 and a photomask 524, for example, wherein the exposure light source 522 may be disposed over the substrate and the photomask 524 may be disposed between the exposure light source 522 and the substrate. The wavelength used in the exposure module 520 can be different from the wavelength used in the measurement module 510. For example, the exposure step may be done with shorter wavelength, such as UV or deep UV radiation, while the measurement step may be done with longer wavelength, such as longer than 500 nm. Preferably, the measurement step may be performed at a wavelength of about 532 nm or 633 nm.

As mentioned above, since the exposure step and the measurement step are performed in the same tool (in-situ) in this invention, the cycle time in the lithography process can be reduced. Moreover, the measurement step is performed after the exposure step and before the development step, so that the measured parameter can be fed back to the exposure module in real time to avoid undesired rework. Meanwhile, since the measurement step is performed before the development step, the accuracy thereof is better without being affected by the process parameters of the development step. Furthermore, this invention adopts an exposure/measurement tool instead of the conventional expensive ACML tool, so that the manufacturing cost can be reduced.

In addition, the scanning precision of the exposure/measurement tool is the same as that of the stepper in current exposure tools, so that the measurement is more precise satisfying the requirements of the next generation of manufacturing process. Moreover, in this invention, sufficient alignment precision of the photosensitive material patterns can be achieved with slight modification, or even without any modification, to the overlay marks. Therefore, the manufacturing cost is not worried about. Furthermore, this invention allows the scribe line regions on a wafer to be narrowed, so that the gross die number of the wafer can be increased.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention covers modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

1. A method for forming a patterned photosensitive material layer, the method comprising: (a) forming a photosensitive material layer over a substrate; (b) exposing the photosensitive material layer and measuring an parameter of the photosensitive material layer; (c) determining whether the measured parameter is acceptable or not; and (d) developing the photosensitive material layer if the measured parameter is acceptable.
 2. The method of claim 1, further comprising the following process before the step (d) if the measured parameter is not acceptable: repeating a step (e) of removing the photosensitive material layer and the steps (a), (b) and (c) in sequence for at least one cycle until the measured parameter is determined to be acceptable in step (c), wherein an exposure condition in step (b) of each cycle is calibrated according to the parameter measured in step (b) of the preceding cycle.
 3. The method of claim 1, wherein the step of exposing the photosensitive material layer produces a latent image in the photosensitive material layer, and the step of measuring the parameter comprises: providing a laser beam; and scanning the latent image with the laser beam and analyzing a signal generated from the laser scanning to obtain a line-width of the latent image.
 4. The method of claim 1, wherein the step of measuring the parameter comprises: providing a laser beam; and scanning exposed portions and non-exposed portions of the photosensitive material layer with the laser beam and analyzing a signal generated from the laser scanning to obtain a thickness difference between the exposed portions and the non-exposed portions of the photosensitive material layer.
 5. The method of claim 1, wherein the step of measuring the parameter comprises: providing a laser beam; and scanning the photosensitive material layer with the laser beam and analyzing a signal generated from the laser scanning to obtain a thickness difference of the photosensitive material layer over the substrate.
 6. A method for forming a patterned photosensitive material layer, the method comprising: (a) forming a photosensitive material layer over a substrate; (b) using an exposure/measurement tool to expose the photosensitive material layer to form a latent image in the photosensitive material layer and using the exposure/measurement tool to measure a parameter of the photosensitive material layer; (c) comparing the measured parameter with a predetermined value; and (d) developing the photosensitive material layer if the measured parameter is smaller than the predetermined value.
 7. The method of claim 6, further comprising the following process before step (d) if the measured parameter is larger than the predetermined value: repeating a step (e) of removing the photosensitive material layer and the steps (a), (b) and (c) in sequence for at least one cycle until the measured parameter is found to be smaller than the predetermined value in step (c), wherein an exposure condition in step (b) of each cycle is calibrated according to the parameter measured in step (b) of the preceding cycle.
 8. The method of claim 7, wherein calibrating the exposure condition according to the measured parameter comprises: feeding back a control signal generated based on the measured parameter to the exposure/measurement tool to order the exposure/measurement tool to calibrate the exposure condition.
 9. The method of claim 6, wherein measuring the parameter comprises: scanning the latent image with a laser beam provided by the exposure/measurement tool; and analyzing a signal generated from the laser scanning to derive a line-width of the latent image.
 10. The method of claim 6, wherein the step of measuring the parameter comprises: scanning the photosensitive material layer with a laser beam provided by the exposure/measurement tool; and analyzing a signal generated from the laser scanning to obtain a thickness difference between the exposed portions and the non-exposed portions of the photosensitive material layer.
 11. The method of claim 6, wherein the step of measuring the parameter comprises: scanning the photosensitive material layer with a laser beam provided by the exposure/measurement tool; and analyzing a signal generated from the laser scanning to obtain a thickness difference of the photosensitive material layer over the substrate.
 12. An apparatus for forming a patterned photosensitive material layer, comprising: a photosensitive material coating tool for coating a photosensitive material layer on a substrate; an exposure/measurement tool for exposing the photosensitive material layer to form a latent image therein and for measuring a parameter of the photosensitive material layer; a development tool for developing the photosensitive material layer; and a substrate carrying tool connected between the photosensitive material coating tool, the exposure/measurement tool and the development tool.
 13. The apparatus of claim 12, further comprising a photosensitive material removal tool that is connected with the exposure/measurement tool via the substrate carrying tool.
 14. The apparatus of claim 13, wherein the photosensitive material removal tool is connected with the photosensitive material coating tool via the substrate carrying tool.
 15. The apparatus of claim 13, wherein the substrate carrying tool carries the substrate to the photosensitive material removal tool or the development tool according to a value of the parameter.
 16. The apparatus of claim 12, wherein the exposure/measurement tool comprises: an exposure module for forming a latent image in the photosensitive material layer; and a measurement module for measuring the parameter of the photosensitive material and for feeding back a control signal generated based on the measured parameter to the exposure module.
 17. The apparatus of claim 16, wherein the exposure module comprises: an exposure light source disposed over the substrate; and a photomask disposed between the exposure light source and the substrate.
 18. The apparatus of claim 16, wherein the measurement module comprises: a laser light source for scanning a line-width of the latent image in the photosensitive material layer; a signal reception device for receiving a test signal generated from the laser scanning that contains information of the line-width; and a signal feedback device for generating the control signal based on the test signal and for feeding back the control signal to the exposure module.
 19. The apparatus of claim 16, wherein the measurement module comprises: a laser light source for scanning the photosensitive material layer; a signal reception device for receiving a test signal generated from the laser scanning that contains information of a thickness difference of the photosensitive material layer on the substrate; and a signal feedback device for generating the control signal based on the test signal and for feeding back the control signal to the exposure module. 